Part way through my RAF flying scholarship, back in the dark ages, the civvy flying school received a C150 which wouldn't fly straight and in balance at the same time after a post-accident rebuild. It always dropped the left wing at the stall.
It was allocated to me and my instructor for a check ride; I had to spin it. From a normal entry it entered the spin very rapidly, flicked then settled and spun inverted, whereupon the engine promptly stopped. My instructor looked very surprised and asked me how I intended to recover. I said I would try easing back on the yoke after full opposite rudder, he nodded. It came out of the spin very quickly and the engine restarted itself as I raised the nose. The instructor abandoned the flight and the aircraft was taken off the flying programme. It was later found to have the wings rigged at different angles!